Planking is very simple. The image above is all the explanation needed. Now, onto the challenge:

Day 1 – 20 seconds

Day 2 – 20 seconds

Day 3 – 30 seconds

Day 4 – 30 seconds

Day 5 – 40 seconds

Day 6 – Rest

Day 7 – 45 seconds

Day 8 – 45 seconds

Day 9 – 60 seconds

Day 10 – 60 seconds

Day 11 – 60 seconds

Day 12 – 90 seconds

Day 13 – rest

Day 14 – 90 seconds

Day 15 – 90 seconds

Day 16 – 120/2

Day 17 – 120/2

Day 18 – 150 seconds

Day 19 – rest

Day 20 – 150 seconds

Day 21 – 150 seconds

Day 22 – 180 seconds

Day 23 – 180 seconds

Day 24 – 210/2

Day 25 – rest

Day 26 – 210/2

Day 27 – 240 seconds

Day 28 – As long as you can tolerate.

So, once the challenge is over that's it, right? Whole new body? Sure, but you can take it a step further.